[AntoineRichard]

Description

Part 15/24 of the asset-test series (tracker: #7282). Depends on #8131; the branch contains its commit until it merges.

This PR moves the PhysX rigid-object-collection tests onto one module-scoped scene of locally authored cubes, instead of a Nucleus DexCube scene per test. The scene has two environments of three gravity-free cubes and one single-cube kinematic collection, run on cpu and cuda:0. PhysX stores collection bodies body-major, so writes select non-sorted environment and body subsets and read the view back. Five nodes:

• Initialization: includes the 1×1 collection; kinematic cubes hold their pose under gravity.
• State writes: non-sorted partial pose and velocity writes. Every body writer is checked with a COM offset, including the cross-frame consistency, plus the spin kinematics about the COM.
• Masses: non-sorted partial mass writes, read back from the body-major view.
• Wrenches: local and global forces, and forces at a position, on every other body; unselected bodies stay at rest.
• Reset: partial and full composer reset assertions, verbatim.

Both regressions added on develop (test_subset_write_reaches_selected_view_entry and #8131's test_inertial_property_subset_writes_reach_selected_view_entries) are kept verbatim in their own scenes. The inertial one runs on a buffer that has never been read. Reverting any of the three #8131 changes turns it red: the COM float view, the COM cache freshness, and the inertia 3-D reshape.

Disposition

Removed develop test	Keeper	Proof
test_initialization (1×1, 2×3)	initialization	assertions carried
test_initialization_with_kinematic_enabled	initialization	assertions carried
test_external_force_on_single_body, ..._at_position	wrenches	mutation: is_global negated; torques zeroed
test_set_object_state	state writes	mutation: partial body pose kernel writes cell (i, j)
test_object_state_properties	state writes (spin)	mutation: COM→link velocity lever sign flipped
test_write_object_state	state writes	mutation: COM→link pose offset sign flipped
test_reset_object_collection	wrenches	verbatim assertions
test_initialization_with_no_rigid_body, test_gravity_vec_w	same tests	kept, local cubes; the gravity rows are now CUDA only

Timing

Warm Warp cache, repository orchestrator (pytest tools), one process per file, second of two runs, RTX 5090. "Before" is develop at 09b1d54. "Before" includes #8131's test.

File	Before	After
test_rigid_object_collection.py	13.2 s (40 tests)	5.1 s (15 tests)

Product bug found (not fixed, not pinned)

A full RigidObjectCollection.reset() still leaves the wrench composers active. reset() passes _ALL_ENV_INDICES to WrenchComposer.reset, which takes the partial-reset path. #8009 reported this. The reset node keeps develop's assertions, which do not check active.

Type of change

• Bug fix (non-breaking change which fixes an issue)

Test-only change; no package code changes.

Release backport

• Backport this pull request to the active release branch after it merges into develop

Checklist

Docker and GPU tests run on demand. Push the commits you want tested, then
comment run-ci on the pull request.

• I have read and understood the contribution guidelines
• I have run the pre-commit checks with uv run isaaclab --format
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have validated the changed behavior with focused coverage and applied the test-audit criteria to any test changes
• I have added a changelog fragment under source/<pkg>/changelog.d/ for every touched package (do not edit CHANGELOG.rst or bump package versions — CI handles that)
• I have added my name to the CONTRIBUTORS.md or my name already exists there

[greptile-apps]

Confidence Score: 4/5

[Medium risk] Fixes physics simulation bugs in rigid object collection.

The PR should not merge until collection tests remain valid when selected alongside own-context tests in a different order.

Findings

1.  Shared scene can lose its stage ▶
2.  Zero offset coverage was removed ▶
3.  Written state is not stepped ▶

Summary

The PR replaces per-test remote-asset scenes with local cubes and a shared PhysX collection scene, while fixing COM and inertia writes and adding subset read-back tests.

• The model-property changes align with the view layouts exercised by the new regression test.
• The shared scene depends on test execution order, and consolidation removes two distinct state-coverage cases.

Diagram

%%{init: {'theme': 'neutral'}}%%
flowchart LR
  A[Own-context tests] --> B[Create and close stage]
  C[Module-scoped collection scene] --> D[Retained PhysX views]
  B -. if run while C is active .-> D
  D --> E[Collection tests]

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_{Reviews (1) · Last reviewed commit: "Run PhysX rigid-object-collection tests ..."}

[greptile-apps]

Shared scene can lose its stage

If a collection test runs before one of the tests that creates its own simulation context, that second test replaces the stage while the module-scoped collection scene is still active. A later collection test then uses PhysX views from the old stage and can fail for a reason unrelated to the behavior it checks. The scene lifetime needs an explicit boundary rather than relying on test order.

Knowledge Base Used: PhysX backend

[greptile-apps]

Zero offset coverage was removed

The consolidated state test only sets a nonzero COM offset. The removed zero-offset case checked that link and COM poses and velocities agree when their frames coincide. Losing that case means a regression in zero-offset frame handling would no longer be caught by this suite.

Note: If this suggestion doesn't match your team's coding style, reply to this and let me know. I'll remember it for next time!

[greptile-apps]

Written state is not stepped

These checks read poses and velocities immediately after each write. The removed state test also advanced physics and checked that the written values persisted. A writer that updates its buffers correctly but loses the state during simulation would now pass this test, so the replacement needs a post-step check.

[AntoineRichard]

Superseded by #8147: the asset-test series was consolidated from 24 to 13 PRs, and this part's changes are now included in #8147 ([8/13]). Series overview: #7282.